got a jvc tv that was dead all but 5v stby, no 12v no backlights went thru the circuit these mains cost over 100. well turns out the culprit was a small transistor marked 2a 3906 switching transistor. if you have a dead board for this set you may want to try checking this marked ua4 right below the lead from the power board and the fuse. it is small and a bugger to get out.